The present invention relates to wound dressings and, more particularly, to a flexible wound dressing product containing a hydrogel substance and a porous layer.
Secreting skin wounds, such as decubitus ulcers and open surgical wounds, have long presented a medical challenge in keeping such wounds sterile and relatively dry. The accumulation in wound crevices of wound exudate, such as blood, pustulation and other wound fluids, promotes growth of bacteria and crusted organisms which cause infection and delay the healing process. However, since it is often desirable to allow a wound to heal in a slightly moist or occlusive state, as it is believed that this may accelerate healing, excess wound exudate must be removed. If excess wound exudate remains on a wound, a "blister" of exudate can form under the wound dressing which is not only unsightly, but also may cause the dressing to leak, thereby defeating the aim of sterility. Existing methods of aspiration, however, can lead to wound infection or can destroy sterility. Additionally, it is not desirable to remove all exudate, as that would result in a dry wound and, hence, a slower healing process.
Known aqueous moisture-absorbing wound dressing systems have additional problems in that the aqueous material is generally contained in the center portion of a wound dressing, with a bulky adhesive border, such as a foam border. Problems with such borders include decreased comfort, conformity and adhesion, as well as the existence of a "lifting edge" that can catch on clothes or bed sheets, thereby exposing the wound to bacteria and infection. In addition, observation of the wound by medical personnel may require lifting the wound dressing, thereby exposing the wound, again creating a situation where bacteria and infection can be introduced to the wound site.
Our own commonly-assigned U.S. Pat. No. 5,106,629, issued Apr. 21, 1992, to Cartmell et al., discloses a hydrogel wound dressing with a thin-film transparent layer, a dimensionally stable backing layer over the outer surface of the transparent layer, and a release liner. The backing layer and the release liner each have a corner tab to facilitate the peeling of each from the transparent layer. The hydrogel material is positioned in a center portion of the transparent layer, and the adhesive perimeter portion of the transparent layer adheres to the skin of the patient. The dimensionally stable backing member prevents the transparent layer from curling and facilitates handling of the dressing during its application.
Many prior art wound dressings contain layers constructed of polyurethane or other polymeric material. Such materials, however, have limited moisture/vapor permeability characteristics. The wound is often not able to breathe adequately. In addition, many wound dressings are difficult to handle and apply to the wound without touching the adhesive portion of the wound dressing.
It is seen, therefore, that there is a need for a hydrogel wound dressing product that is easily handled during application to the wound without touching the adhesive side of the dressing. Further, there is a need for a hydrogel wound dressing product that contains a porous, moisture- and vaporpermeable layer.